<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 
<html> 
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-15"> 
<title>Probando window.open</title> 
<script type='application/javascript'> 
	var contenido = "<html><head><title>Mis ventanas</title></head><body><h1>Mis ventanas</h1></body></html";
	var numero_ventanas = Math.floor(10*Math.random());
	for (var i=0; i<numero_ventanas; i++){ 
		newwindow=window.open(); 
		newdocument=newwindow.document; 
		newdocument.write(contenido);
	}
</script>
